There is no criteria. Anyone who calls themselves Christian is a Christian. The same goes for any other religion. All religions have differing internal beliefs, so there is no objective definition of a “true believer.”

I believe it's not the same for any other religion. For example conversions to Judaism are overseen by a religious court.

An actual court in the US will probably not try to legislate whether a person is of the Jewish faith or not, _regardless_ of what some other religious "court" says.

Probably (IANAL) if a person says that they observe the Jewish faith and that this is a deeply held belief, regardless of whether some religious organization recognizes him/her, that will be enough for the courts.

Sorry, I was talking from the believer's point of view; not from a law perspective. You are probably right about that.

> It is a religion, with many denominations.

The whole of it defies neat categorization. People who self-describe as Christians can't even universally agree which texts are authentic and holy and which are heretical frauds. The only thing they all universally share is the inclination to call themselves Christians (more than a few are eager to contest whether other self-described Christians are in fact Christians.)

One particular example: I was raised to believe that the Book of Mormon is a heretical fraud, and consequently to believe that Mormons are not real Christians (despite claiming to be.)

> People who self-describe as Christians can't even universally agree which texts are authentic and holy and which are heretical frauds. The only thing they all universally share is the inclination to call themselves Christians.

Interesting perspective- when I was much younger, I was taught that a Christian is anybody who believes that Christ is the Savior and that he atoned for the sins of humanity. Is there an "official" definition?

It doesn't matter whether it's "considered" Christian or not. All that matters legally is whether it's a sincerely held religious belief.